煤化工金属密封耐磨球阀高频振动机理研究及结构优化

发布时间：2018-02-25 18:29

本文关键词： 金属密封耐磨球阀振动结构优化数值模拟　出处：《沈阳工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：在煤化工行业中以输送高温、高压、高流速并含有固体颗粒介质管路中的阀门工况条件最为恶劣。目前在煤液化装置中所使用的大部分金属密封耐磨球阀采用进口产品,虽然进口产品技术相对成熟,但质量参差不齐。并且该类阀门价格昂贵、供货周期长,很难满足市场的需求。而国内该类阀门的抗振性能、耐磨性能和密封性能不能得到保证亟待解决。针对这一重要课题,本文以煤化工金属密封耐磨球阀国产化为背景,对该类阀门的核心部件结构进行深入探究,并进行结构优化,从而解决金属密封球阀高频振动等技术问题,实现该类阀门的国产化。本文首先对金属密封耐磨球阀振动机理进行理论分析,并建立数学模型。在理论的指导下,经过计算,得到固有频率公式以及共振条件。分析金属密封耐磨球阀结构参数和流动参数对其固有频率的影响规律,通过调整结构尺寸,改变固有频率,来防止产生共振,从而优化金属密封耐磨球阀结构。根据煤化工工况要求,自主设计一种方心流道金属密封耐磨球阀。阀球、阀座采用特有的360°逐步镜面配磨技术,可以使阀球与阀座之间形成镜面的真空状态,它的密封性能在频繁开关后仍然能够得到保证。此外阀球、阀座采用金刚石喷涂技术,能够显著提高其硬度和耐腐蚀性能。通过对金属密封耐磨球阀关键结构进行优化设计,并进行强度校核和抗振性校核,确定阀门结构尺寸,保证阀门的使用性能以及在煤化工装置连续稳定运行。通过数值模拟发现,本课题设计的方心形流道金属密封耐磨球阀在相同条件下,不同开度的阀球、阀座关键部位所受冲击力比普通圆形流道的金属密封耐磨球阀减小,耐磨性得到提高,大大延长其使用寿命。此外通过振动特性数值模拟,得到流体固有频率分析值不满足阀门发生共振条件,进一步验证对阀门振动特性理论研究的正确性,减小高频振动对阀门产生的影响及危害,阀门的使用性能得到提高。最后进行压力试验和模拟工况试验。实验结果表明该设计阀门在煤化工耐磨工况下,阀门动作灵活、无卡阻。阀球和阀座密封副的密封性能及阀杆柔性石墨环组合填料密封性能优异。喷涂层在耐磨工况下无脱落具有良好的耐冲蚀磨损能力。并且该阀门在管路系统中平稳运行三个月,未发生共振情况,达到了本文自主研制高性能阀门的设计要求。
[Abstract]:In coal chemical industry, the working conditions of valves in conveying high temperature, high pressure, high flow velocity and containing solid particles are the worst. At present, most of the metal sealing ball valves used in coal liquefaction equipment adopt imported products. Although the imported product technology is relatively mature, the quality is not uniform. Moreover, the price of this kind of valve is expensive, the supply period is long, it is very difficult to meet the market demand. The wear resistance and sealing performance can not be guaranteed urgently. In view of this important subject, this paper, based on the localization of metal seal ball valve in coal chemical industry, makes a deep research on the structure of the core parts of this kind of valve, and optimizes the structure of the valve. In order to solve the technical problems such as high frequency vibration of metal sealing ball valve and realize the localization of this kind of valve, this paper first makes a theoretical analysis on the vibration mechanism of metal seal wear resistant ball valve, and establishes a mathematical model. The natural frequency formula and resonance condition are obtained. The influence of structure parameters and flow parameters of metal seal ball valve on its natural frequency is analyzed. By adjusting the structure dimension and changing the natural frequency, the resonance is prevented. In order to optimize the structure of metal seal wear resistant ball valve, according to the requirement of coal chemical engineering, a square core flow channel metal seal wear resistant ball valve is designed independently. The valve ball, valve seat adopts special 360 掳step by step mirror grinding technology, The vacuum state between valve ball and valve seat can be formed, its sealing performance can still be guaranteed after switching frequently. In addition, valve ball, valve seat adopts diamond spraying technology, Can significantly improve its hardness and corrosion resistance. Through the optimization of the metal seal wear resistant ball valve key structure design, strength check and vibration resistance check, determine the valve structure size, Through numerical simulation, it is found that the square heart-shaped flow channel metal seal wear resistant ball valve is designed under the same conditions, and the valve ball with different opening degree is found by numerical simulation. The impact force on the key parts of the valve seat is reduced compared with the metal seal ball valve of the ordinary circular flow channel, and the wear resistance is improved, which greatly prolongs its service life. In addition, through the numerical simulation of the vibration characteristics, The analysis value of natural frequency of fluid does not satisfy the resonance condition of valve, which further verifies the correctness of theoretical research on the vibration characteristics of valve, and reduces the influence and harm of high frequency vibration on valve. The performance of the valve has been improved. Finally, the pressure test and simulated condition test are carried out. The experimental results show that the valve is flexible in operation under the wear-resistant condition of coal chemical industry. The sealing performance of valve ball and seat seal pair and the sealing performance of valve stem flexible graphite ring combination packing are excellent. The spray coating has good erosion resistance and wear resistance under wear-resistant condition, and the valve is in the pipeline system. The system runs smoothly for three months, No resonance occurred, which met the design requirements of the self-developed high-performance valve in this paper.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ53;TQ055.8

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